Indecisive prince heading off to secure king's band (6)
I believe the answer is:
armlet
'band' is the definition.
(I know that armlet is a type of band)
'indecisive prince heading off to secure king's' is the wordplay.
'indecisive prince' becomes 'Hamlet' (To be or not to be. Prince Hamlet from Shakespeare).
'heading off' means to remove the first letter.
'to secure' means one lot of letters goes inside another (inserted letters are secured inside).
'king' becomes 'R' (abbreviation for rex, king in Latin).
'hamlet' with its initial letter taken away is 'amlet'.
'amlet' going around 'r' is 'ARMLET'.
(Other definitions for armlet that I've seen before include "brassard" , "Member may be surrounded by this" , "A band on the upper biceps" , "Martel (anag.)" , "Form of bracelet" .)